Protein discovery could revolutionise PCN control

Improved methods for controlling the potato cyst nematode Globodera pallida are a step closer thanks to the discovery of a family of protein molecules that help the nematode attack plant roots.

Currently there are few commercial potato varieties with resistance to G pallida, so growers have to rely on expensive nematicides and extending rotations to reduce populations. However, both have an impact on growers’ bottom line and the industry is crying out for an alternative.

But resistant varieties and a new wave of nematicides could be on their way thanks to a joint research project between SCRI, Leeds University, Rothamsted Research and the Wellcome Trust Sanger Institute.

Scientists had used genome sequencing to discover a family of “effector” proteins, which could help in the development of alternative PCN controls, said SCRI plant pathologist John Jones at the Crop Protection in Northern Britain conference. “It is thought the nematode uses these effector proteins to suppress plant defences allowing them to attach themselves to roots unhindered.”

The nematode secreted these effector proteins into plant roots allowing it to establish a feeding site and draw nutrients from the plant, he explained. But it was possible some of the effector proteins could be detected by host plants, he said. “If effectors are recognised by the host this allows it to mount a resistant response – the challenge is to work out what they do and which are recognised by the host.”

Once effector proteins had been mapped they could be used to search through plant genetic material to locate genes that would trigger a response against G pallida, he said. “The ability to screen potato breeding lines with nematode effectors in order to identify those that contain nematode resistance genes will help breeders develop varieties with resistance to G pallida.” Similar techniques were being deployed to identify resistance against the late blight pathogen.

The genome project would generate a full list of the genes present in G pallida making identification of new control strategies more straightforward, he added. “The genome sequence will allow essential G pallida enzyme pathways or important genes specific to G pallida to be identified.”

These could then be targeted through GM breeding approaches or used to develop a new breed of specific nematicides, he concluded.